Collaborative development of various documents had traditionally been done within the confines of a secure network, such as that of a corporation or other business entity. For example, reports, product requirements, and other documents were created and revised by users accessing the secure network. With the advent of high-speed communications and mobile devices such as notebook computers, tablet computers, and smart phones, collaborative development has been extended beyond secure networks.
Extra security measures are often employed with documents being accessed beyond the secure network. For example, data authentication and encryption may be used to ensure that data is received from a trusted source and has not been tampered with, and that the data cannot be intercepted and accessed by an unauthorized party.
Though documents have been encrypted and made available in shared storage, such as on storage provided by servers connected to the Internet, users may desire to search for documents having words and/or phrases that match specified search queries. However, maintaining secrecy over information contained in the documents may impede providing search functions. Storing plaintext words, key words, and phrases on the server(s) to aid in searching would be undesirable as information about the files may be leaked.
Managing the authentication and encryption keys is challenging when a particular document may be accessed by many different users, and each user may access that document with a number of different devices. Not only must the security of the document be maintained, but the security mechanism must not be so cumbersome that undue burdens are imposed on those accessing the document.